In virtualization environments, a hypervisor may map various hardware on a host machine to a virtual machine. Unlike other hardware resources, such as multi-core processors and disk storage which can be partitioned, audio hardware such as a sound card may not be easily partitioned. In a multi-virtual-machine environment, the hypervisor may allow only one virtual machine to access a sound card at a time, in order to avoid conflicts in processing concurrent audio instructions, or multiple audio streams to overload the sound card. However, a rigid assignment of a sound card to one virtual machine may impair user experience across other virtual machines, such as where a user may rely on audio cues from background virtual machines, or may desire access to audio playback from multiple virtual machines.